An important challenge to future communications is to realize seamless handover of multimedia services in fixed and mobile networks so that users can enjoy uninterrupted services anywhere at any time. When a user or a user equipment (UE) moves in the transport path of different networks, to bring better service experience to the user, a fast and short-delay seamless handover is required.
In a network resource reservation solution in the prior art, a method based on a centralized resource and admission control system can provide the network resource reservation service to reserve network resources for a user according to the resource status of the current network and the service policy of the user.
As shown in FIG. 1, in a resource and admission control function (RACF), a policy decision function entity (PD-FE) receives a resource request from a service control function (SCF) and makes a comprehensive decision according to the service request, network policy and the transport subscription information of the user, and requests a transport resource control function entity (TRC-FE) and a policy enforcement function entity (PE-FE) to assign access and core transport resources, thus realizing resource reservation.
As seen from above, the prior art has the following drawback:
The above network resource reservation solution based on a centralized resource and admission control system can only reserve network resources with respect to the current path of the user. The RACF controls the resource assignment for user sessions. At one moment, with respect to the current user, the RACF has only one resource reservation record.
The solution in the prior art is unable to reserve network resources in advance on the possible target transport path before a network handover actually occurs, when a UE is moving. The solution can only release network resources on the transport path before the handover and then reserve network resources on the target transport path for the user after the path handover actually occurs. The handover causes a long delay and as a result, the quality of the ongoing service of the user drops and the service is even interrupted.